Nibbled leaf fossils and prehistoric bugs

If you give the same kind of pizza to a group of kids, some kids might just eat the cheese, some might pick off the pepperoni, others might leave the crusts. Afterward, the plates of leftovers would look pretty different from each other.

Leaf-eating bugs are just the same way.

Many of these insect species have their own personal style of eating through leaves. So, if you know what to look for, you can tell which kind of bug has been munching on a leaf.

A team of scientists has studied fossils of prehistoric leaves that lived shortly after a mass-extinction 65 million years ago. Many plants and animals (including the dinosaurs) were wiped out during this event.

The researchers studied thousands of leaves from spots all over the western United States. They compared the number of plant species from this time with the number of bug species that had chewed on the plants.

The research team, led by Peter Wilf of Pennsylvania State University, learned that in some ways these two types of organisms may not be as dependent on each other as we thought.

Scientists have generally thought that if you had lots of plants species, then you'd also have a lot of plant-eating insect species. Overall, this seemed to be true for the leaf fossils in the study. But, there were some interesting exceptions, where there were either many more bug species than leaf species, or vice versa.

These findings may help scientists understand how food webs recover after mass extinctions. The study appears in the 25 August 2006 issue of the journal Science.